TY - JOUR
T1 - Direct evidence for tonic sympathetic support of resting metabolic rate in healthy adult humans
AU - Monroe, Mary Beth
AU - Seals, Douglas R.
AU - Shapiro, Linda F.
AU - Bell, Christopher
AU - Johnson, David
AU - Jones, Pamela Parker
PY - 2001/5
Y1 - 2001/5
N2 - The sympathetic nervous system (SNS) plays an important role in the regulation of energy expenditure. However, whether tonic SNS activity contributes to resting metabolic rate (RMR) in healthy adult humans is controversial, with the majority of studies showing no effect. We hypothesized that an intravenous propranolol infusion designed to achieve complete β-adrenergic blockade would result in a significant acute decrease in RMR in healthy adults. RMR (ventilated hood, indirect calorimetry) was measured in 29 healthy adults (15 males, 14 females) before and during complete β-adrenergic blockade documented by plasma propranolol concentrations ≥100 ng/ml, lack of heart rate response to isoproterenol, and a plateau in RMR with increased doses of propranolol. Propranolol infusion evoked an acute decrease in RMR (-71 ± 11 kcal/day; -5 ± 0.7%, P < 0.0001), whereas RMR was unchanged from baseline levels during a saline control infusion (P > 0.05). The response to propranolol differed from the response to saline control (P < 0.01). The absolute and percent decreases in RMR with propranolol were modestly related to baseline plasma concentration of norepinephrine (r = 0.38, P = 0.05; r = 0.44, P = 0.02, respectively). These findings provide direct evidence for the concept of tonic sympathetic β-adrenergic support of RMR in healthy nonobese adults.
AB - The sympathetic nervous system (SNS) plays an important role in the regulation of energy expenditure. However, whether tonic SNS activity contributes to resting metabolic rate (RMR) in healthy adult humans is controversial, with the majority of studies showing no effect. We hypothesized that an intravenous propranolol infusion designed to achieve complete β-adrenergic blockade would result in a significant acute decrease in RMR in healthy adults. RMR (ventilated hood, indirect calorimetry) was measured in 29 healthy adults (15 males, 14 females) before and during complete β-adrenergic blockade documented by plasma propranolol concentrations ≥100 ng/ml, lack of heart rate response to isoproterenol, and a plateau in RMR with increased doses of propranolol. Propranolol infusion evoked an acute decrease in RMR (-71 ± 11 kcal/day; -5 ± 0.7%, P < 0.0001), whereas RMR was unchanged from baseline levels during a saline control infusion (P > 0.05). The response to propranolol differed from the response to saline control (P < 0.01). The absolute and percent decreases in RMR with propranolol were modestly related to baseline plasma concentration of norepinephrine (r = 0.38, P = 0.05; r = 0.44, P = 0.02, respectively). These findings provide direct evidence for the concept of tonic sympathetic β-adrenergic support of RMR in healthy nonobese adults.
KW - Resting energy metabolism
KW - Sympathetic nervous system
KW - β-adrenergic blockade
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U2 - 10.1152/ajpendo.2001.280.5.e740
DO - 10.1152/ajpendo.2001.280.5.e740
M3 - Article
C2 - 11287356
AN - SCOPUS:0035010368
SN - 0193-1849
VL - 280
SP - E740-E744
JO - American Journal of Physiology - Endocrinology and Metabolism
JF - American Journal of Physiology - Endocrinology and Metabolism
IS - 5 43-5
ER -